In networks that operate at high carrier frequencies, such as the millimeter wave (mmW) band or in bands that are higher than those used by conventional cellular networks such as Long Term Evolution (LTE) and High Speed Packet Access (HSPA), the link between an access node (AN) and the wireless device (WD) may depend on high gain directivity to limit interference in the network and to provide high signal-to-noise ratio (SNR) links.
FIG. 1 is a schematic illustration of beam finding resulting in varying signal-to-noise ratios experienced by different wireless device. The radios in the network may have varying capabilities. FIG. 1 shows two established links from an AN to two WDs (WD1 with high SNR and WD2 with low SNR) and several potential links to WDs in the coverage area of the AN. The environment is prone to spotty coverage and SNR can vary significantly between WDs. In addition, WDs in the network can have varying capabilities such as the use of analog vs. digital beam-forming. There is therefore a possibility of widely varying SNRs between various links in the network.